Looking at the method implementation, it looks like there might be a problem
here.
new_uuid() ->
list_to_binary(to_hex(crypto:rand_bytes(16))).
In particular, we aren't actually guaranteed to have a unique value.
You can read more about what needs to be done to get unique guids: here:
http://blogs.msdn.com/oldnewthing/archive/2008/06/27/8659071.aspx